Set the VAT rate, nature code and split payment on an invoice in SamBooks
8 min read
Every invoice line has a VAT code field that sets the rate and nature, and for PA customers, split payment. Here is how to use it and what happens if you err.
What this is for
The "VAT code" field on each invoice line isn't just the percentage: it's a named code that picks a rate and, when needed, a nature code (the reason the rate is zero) together. SamBooks blocks the combinations SDI would reject before you can even save: you can't save a line with a rate above zero AND a nature code together, nor a zero-rate line with no nature code at all.
Before you start
Every company already has a ready-made catalog of VAT codes (the most common rates and the most frequent exemptions). If the case you need isn't in there, you can still go ahead right on the line using "Advanced," covered in step 3.
How to do it, step by step
1. Choose the VAT code on the line
On the invoice line, in the "VAT code" field, open the dropdown: the codes are grouped by category (Taxable, Excluded / not subject, Non-taxable, Exempt, Special regimes, Reverse charge), and you can search by typing ("Search VAT code…"). Once you pick one, SamBooks fills in the rate and, if needed, the nature code by itself — you never touch them by hand.
2. If you can't find the right code: check the company's catalog first
The code names are whatever your company has configured (e.g. "VAT 22%," "Non-taxable - export"): if the catalog is missing your case, you can add a new one from Company settings → VAT codes before going back to the invoice.
3. Otherwise, use "Advanced" right on the line
If no code in the catalog fits, below the VAT code field you'll find the "Advanced (rate + nature by hand)" option: two separate fields open, "VAT %" and "VAT nature." The same rule always applies here:
- if you enter a rate above zero, the Nature field must stay empty ("None (with VAT)");
- if you leave the rate at zero, the Nature field becomes visibly required and must be filled in, or saving is blocked.
4. Pick the right nature among the leaf codes
The VAT nature selector only offers leaf codes: N1, N2.1, N2.2, N3.1, N3.2, N3.3, N3.4, N3.5, N3.6, N4, N5, N6.1, N6.2, N6.3, N6.4, N6.5, N6.6, N6.7, N6.8, N6.9, N7. The generic codes N2, N3, and N6 (without a decimal number) still exist in the FatturaPA schema but haven't been valid with SDI since 2021: that's why SamBooks doesn't even list them, so you can't pick them by mistake.
5. The same rule applies to shipping charges
If you fill in an amount for shipping charges in the header, the rate-nature block applies exactly the same way: an amount with a 0% rate still needs a nature code, or saving fails through the same mechanism as line items.
6. Split payment: set it on the customer, not on the invoice
If the customer is a Public Administration body or an equivalent entity, split payment isn't a field you choose line by line: it's a property of the customer record. In the invoice's customer box you'll find the "Split payment" field with the text: "PA customer/equivalent entity: the invoice is issued with 'split payment' VAT chargeability (art. 17-ter DPR 633/72). Pre-filled from the selected customer." — if you turn it on (or it's already on for that customer's record), every invoice to that customer is automatically created with this chargeability, with nothing more to do on the lines. You can change the field from the invoice's own customer box: the change stays saved to the customer record for future invoices.
7. Reverse charge on a sale: a normal line on an ordinary invoice
For a reverse-charge sale (e.g. construction subcontracting, scrap metal) you don't need a special document type: it stays a normal TD01 invoice. On the line, pick a code with nature N6.x (or, in Advanced, set the rate to 0 and the nature to N6.1-N6.9): the line ends up with no VAT charged, and the nature code states why.
8. SamBooks calculates VAT chargeability — you don't choose it
The document also carries a VAT chargeability (immediate, deferred, or split payment), but it isn't a field you fill in on the invoice: SamBooks works it out on its own — split payment if the customer has that status (step 6) or if a line posts to an account configured for split payment, immediate in every other case.
9. Check the result in the VAT summary
On the invoice detail, "Details" tab, the "VAT summary" section groups every line by Rate, Nature, Taxable amount, and Tax: it's the fastest way to check, before sending, that every rate/nature combination is the one you meant.
If you get it wrong: what happens
- Rate above zero plus a nature code filled in together: saving doesn't succeed. In "Advanced" mode, the Nature field doesn't even appear once the rate is above zero, specifically to prevent this mistake.
- Zero rate with no nature code: the VAT nature field marks itself as required (a starred label) as soon as the rate drops to zero; if you leave it empty, saving stays blocked until you fill it in.
- An error that shows up after sending to SDI (not before, at save time): if a line's issue slipped past local validation, the invoice comes back "Rejected by SDI" with a precise code — for example
00400("The Nature code is missing on a line with 0% VAT") or00445("You're using a generic Nature code (N2, N3, N6) that hasn't been valid since 2021"). The guide on a rejected invoice explains how to read it and fix it.
Ask Sam
You can ask Sam to create the invoice specifying the rate or nature per line directly — for example, "invoice to customer Rossi, one consulting line for €1,000, nature N4 exempt" — and Sam applies the same rate-nature consistency rule covered in this guide: if the combination doesn't add up, the creation stops with the same kind of error you'd see in the UI.
Frequently asked questions
What VAT nature code should I use? It depends on the type of transaction: SamBooks presents the codes as named "VAT codes," already grouped by category (Exempt, Non-taxable, Excluded/not subject, Special regimes, Reverse charge) in the company's catalog — pick the one whose name matches your case, or use "Advanced" if you already know the N-code you need.
How do I create a VAT-exempt invoice? Pick a VAT code from the "Exempt" category in the catalog, or in "Advanced" set the rate to 0 and the nature to N4.
Which code do I use for a non-taxable invoice? Look among the codes in the "Non-taxable" category in the catalog, or in "Advanced" use rate 0 with the specific N3 nature code (N3.1-N3.6 depending on the case).
What does N2.2 mean? It's one of the leaf codes offered by the VAT nature selector when the rate is zero: it appears in the list alongside N1, N2.1, N3.1-3.6, N4, N5, N6.1-6.9, and N7.
It tells me a 0% rate needs a nature code: why? It's the consistency rule SamBooks applies on every line (and on shipping charges): a zero rate must always state the reason with a Nature code, or SDI would reject it with error 00400.
How do I create a reverse-charge invoice? It's a normal TD01 invoice: on the line, pick a code with N6.x nature instead of a rate. No different document type is needed.
How do I invoice a Public Administration with split payment? Turn on "Split payment" on the customer (in the invoice's customer box or in the customer record): from then on, every invoice to that customer is created with the correct chargeability already set, with nothing to touch on the lines.
What is split payment? It's the VAT chargeability SamBooks applies automatically when the customer on the invoice is a Public Administration body or an equivalent entity with split payment turned on in their record.
What's the difference between exempt and non-taxable on an invoice? In the product they're two distinct categories in the VAT codes catalog ("Exempt" and "Non-taxable"), each with its own nature codes (N4 for exempt, N3.x for non-taxable): pick the category matching your case from the dropdown.
What VAT do I use for a foreign customer? Look among the codes in the "Non-taxable" or "Excluded / not subject" categories in the company's catalog: if there's no ready-made code for your case, use "Advanced" with the rate and nature you need.
How do I set deferred VAT chargeability? In the invoice creation form it isn't a field you fill in: SamBooks calculates the chargeability itself (split payment for PA customers, immediate otherwise) based on the customer and the accounts used on the lines.
My invoice was rejected over the nature code: what do I do? Open the "SDI Events" tab on the detail page: the code (e.g. 00400 or 00445) and its plain-language description tell you exactly what's missing or needs replacing. The guide on a rejected invoice covers the whole fix path.
N2 isn't valid anymore: what do I use instead? SamBooks' VAT nature selector no longer offers plain N2 on its own: pick the specific leaf code, N2.1 or N2.2, depending on your case.